The Supreme Court decision upholding the federal ban on a controversial abortion procedure started playing out in Virginia yesterday, as the justices ordered a Richmond-based appellate court to reconsider the state law it struck down barring the procedure.

In 2005, the U.S. Court of Appeals for the 4th Circuit overturned Virginia's ban on what opponents call "partial birth infanticide." A three-judge panel, citing Supreme Court precedent, found the measure unconstitutional because it lacks an exception to safeguard a woman's health.

But the Supreme Court reversed course last week, upholding the Partial Birth Abortion Ban Act passed by Congress in 2003. Yesterday, the high court followed up by vacating the 4th Circuit decision and sending the case back to Richmond for review, "in light of" the ruling last week. A similar appellate court decision striking down Missouri's ban on the procedure also will be reconsidered.

The Supreme Court's decision marked the first time justices have agreed that a specific abortion procedure could be banned. Yesterday, abortion rights supporters and opponents agreed that the 4th Circuit could reverse itself and allow the Virginia ban to take effect.

"We're concerned because the Supreme Court has taken a major shift in its jurisprudence, and the Court of Appeals could follow the Supreme Court," said Nancy Northup, president of the Center for Reproductive Rights. The New York-based group challenged the Virginia law on behalf of a Richmond doctor and a Richmond medical center.

If the Virginia ban takes effect, Northup said, "it would put doctors under pressure from both state and federal prosecutors."

Tucker Martin, a spokesman for Virginia Attorney General Robert F. McDonnell (R), said he is "confident that the 4th Circuit will follow the lead of the Supreme Court." McDonnell, whose office represents the state, applauded the Supreme Court decision last week and said it "recognizes the dignity of human life."

The 4th Circuit's earlier decision striking down Virginia's law was written by Judge M. Blane Michael and joined by Judge Diana Gribbon Motz, both appointees of President Bill Clinton, a Democrat. Judge Paul V. Niemeyer, an appointee of President George H.W. Bush, dissented. Under 4th Circuit procedures, the same three judges will take up the case again.

The Virginia law, passed in 2003 over the objections of then-Gov. Mark R. Warner (D), was similar to the national ban approved by Congress that year. Both measures made it a crime for doctors to perform the procedure.

The procedure, used in a limited number of midterm abortions, is known as an "intact dilation and evacuation." It involves partly delivering the fetus and then crushing the skull to make removal easier. Some physicians say that in certain circumstances, it is better for a woman to undergo this type of abortion because it carries a lower risk of bleeding, infections and permanent injury.

Opponents say the procedure blurs the line between abortion and infanticide.

Legal experts familiar with the 4th Circuit said yesterday that the court is likely -- but not certain -- to reverse its earlier ruling and allow Virginia's ban to take effect.

"It's not entirely clear, but it seems likely that the 4th Circuit may now sustain the Virginia statute," said Carl Tobias, a constitutional law professor at the University of Richmond.

Michael Gerhardt, a professor of constitutional law at the University of North Carolina, said that last week's Supreme Court decision increases the chances of a 4th Circuit reversal but that it "may not definitively determine the outcome." He said the 4th Circuit could order a lower court to hold hearings on how the Virginia law would be enforced.

If the courts determine that the law imposes an "undue burden" on a woman's legal right to choose an abortion, Gerhardt said, the 4th Circuit could again throw out the Virginia law.